1. Field of the Invention
This invention relates to an electro-optic device. More particularly, the present invention pertains to a display device using an electro-optic substance such as liquid crystal, electrochromy, etc.
2. Description of the Prior Art
In electro-optic devices, particularly liquid crystal display devices, for the purpose of effecting simple or easy connection between electrode terminal portion in the outer electronic circuit for driving said device and the electrode terminal portion of the liquid display device, there has generally been adopted a system in which the substrate having a display electrode provided thereon is elongated in the longitudinal direction longer than the counterelectrode substrate; the terminal electrodes from the display electrodes and the electrodes for shortcircuit of counterelectrodes are arranged concentratedly on the portion protruded out of the overlapped portion when both substrates are opposed to each other. With such an arrangement, in some cases, there may occur cross-over between the lead electrodes of the upper and lower substrates in the course of leading out the electrodes to the terminals. On the other hand, in liquid crystal display devices, the effective display area is desired to be as large as possible and hence cross-over of lead electrodes on the upper and lower substrates has been designed to be done at the outside of the seal spacer. Particularly, in recent liquid crystal display devices, there is frequently used a dynamic drive system to simplify the electrode structure. As an advantage by adoption of a dynamic drive system, there may be mentioned marked decrease in number of the lead wires as compared with those in the electrode structure employed in a static drive system of prior art. For example, each segment electrode in an electrode structure having plural number of segments of a figure 8 (multi-digit display) arranged in parallel is to be electrically connected through lead electrodes to the terminals arranged concentratedly on one of the substrates, lead electrodes for the common electrode are arranged in the horizontal direction to make each electrode electrically in parallel to each other. As the result, there is caused cross-over at some points between the horizontally arranged lead electrodes for common electrodes and the lead electrodes for the counterelectrodes which are vertically arranged. When such a cross-over exists within the portion filled with liquid crystal it will appear as an unnecessary display. For this reason, the cross-over as described above has been intended to occur outside the seal spacer.
Whereas, in a device having such opposite electrodes outside the seal spacer, moisture tends to adhere to the space between these electrodes during usage for a long period. Moreover, since the space between the two substrates in a conventional liquid crystal display device is as small as 0.3 to 30 microns, preferably 0.6 to 15 microns, moisture droplets that adhere once to the space cannot easily be removed. As a consequence, these moisture droplets that adhere to the space between the electrodes may be electrolyzed on the electrodes by current passage between the electrodes, whereby the wires at electrodes may be broken. Further, when an electroconductive minute impurity exists in the space between the electrodes, it may also excite a shortcircuit state to cause erroneous actuation.